Friction stir stationary shaft shoulder, friction stir welding tool and use method of friction stir stationary shaft shoulder and friction stir welding tool

Abstract

The invention discloses a friction stir stationary shaft shoulder, a friction stir welding tool and a using method of the friction stir stationary shaft shoulder and the friction stir welding tool, and belongs to the technical field of friction stir welding. The friction stir stationary shaft shoulder comprises a shaft shoulder end face, a guide groove, a rear pressing face and a cutting edge face, and the guide groove is arranged on the rear portion of the outer side of the shaft shoulder end face in a semi-ring shape on the radial projection face in an adjacent and annular mode. The rear pressing face is arranged on the periphery of a groove opening of the guide groove in a semi-ring shape on the radial projection face, and the end face of the shaft shoulder protrudes out of the rear pressing face in the axial direction. The cutting edge faces are vertically arranged at the front end of the rear pressing face and distributed outside the two opposite sides of the shaft shoulder end face, and cutting edges are arranged at the positions, located on the outer sides of the guide grooves, of the lower ends of the cutting edge faces. According to the friction stir stationary shaft shoulder, the flash can be removed on line while welding is carried out, a weld joint without the flash is obtained completely, and the friction stir stationary shaft shoulder has the advantages of interference avoidance, convenience in processing and low price.

Description

Technical Field

[0001] The invention relates to the technical field of friction stir welding, and in particular to a friction stir welding stationary shoulder, a friction stir welding tool and a use method thereof. Background Art

[0002] The stationary shoulder friction stir welding process (SSFSW) is an extension of the friction stir welding technology. Friction stir welding is a solid phase welding method, which generally requires a stirring head to penetrate into the plate to be welded, rotate and feed on the XY plane, relying on friction and deformation to generate heat to bridge the materials. The stirring head generally has two key structures, namely the needle tip part and the shoulder part. During welding, the needle tip part penetrates into the plate to be welded, and the shoulder part presses the surface of the plate to be welded. The shoulder part generates a lot of heat during welding, resulting in an uneven weld temperature field, a high surface temperature, and good surface material fluidity, which not only causes serious thermal deformation of the workpiece, but also easily causes flash on both sides of the weld. Therefore, in order to control excessive heat generation and excessive flash on the shoulder, the stationary shoulder friction stir welding process has emerged. During welding, the shoulder is actually stationary, and only the center needle tip rotates. The SSFSW process effectively controls the thermal deformation and flash of the material. However, in actual production, due to various factors such as uneven plate thickness and pressure fluctuations, a small amount of flash still exists on both sides of the weld of the welded product. The surface of the welded product cannot reach a state where it can be directly processed to the next process without grinding. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the first aspect of the present invention is to provide a stir friction stationary shoulder, which can remove flash online while welding to obtain a completely flash-free weld, and has interference avoidance, is easy to process, and is cheap.

[0004] The friction stirring stationary shoulder according to the first aspect of the present invention comprises: Shoulder end face; A material guide groove, which is semi-circular in shape on a radial projection surface and is arranged adjacent to the outer rear of the shaft shoulder end surface; A rear pressure surface, which is semi-annular in radial projection and is closely arranged around the outer periphery of the slot of the material guide slot, and the shaft shoulder end surface protrudes from the rear pressure surface in the axial direction; The cutting edge surface is vertically arranged at the front end of the rear pressure surface and distributed outside the opposite sides of the shoulder end surface. The lower end of the cutting edge surface is provided with a cutting edge at the outer side of the material guide groove.

[0005] The stirring friction static shoulder of the first aspect of the embodiment of the present invention has the following advantages: on the one hand, the material guide groove and the rear pressure surface can limit the warped burrs overflowing from the peripheral edge of the shoulder end face, the material guide groove can effectively capture the warped burrs at the peripheral edge immediately behind the shoulder end face, the cutting edge can synchronously and effectively cut off the overflowing burrs located radially outside the front end groove of the material guide groove online in real time, the rear pressure surface can effectively flatten the warped burrs captured by the material guide groove and the part after the burrs are cut off by the cutting edge, thereby, the obtained weld is completely burr-free and the weld surface is smooth, so that the post-weld product eliminates the burr removal grinding process; on the other hand, the stirring friction static shoulder is small in size, will not interfere with other components, has interference avoidance, is easy to process, and is inexpensive.

[0006] In some embodiments, the axial distance between the shoulder end surface and the rear pressure surface is 0.25-0.5 mm.

[0007] In some embodiments, the groove depth of the material guide groove is 0.5~1.5mm, and the groove width of the material guide groove is 0.6~1.5mm.

[0008] In some embodiments, the length of the cutting edge is at least 0.4 mm.

[0009] In some embodiments, the cutting edge is directly formed at the lower edge of the cutting edge surface; or, a blade is fixed on the cutting edge surface, and the blade edge of the blade is the cutting edge.

[0010] In some embodiments, the front side of the cutting edge surface forms an open space area.

[0011] A second aspect of the present invention provides a friction stir welding tool.

[0012] The friction stir welding tool according to the second embodiment of the present invention comprises the friction stir stationary shoulder described in the first embodiment of the present invention.

[0013] Since the friction stir welding tool of the second embodiment of the present invention adopts the friction stir stationary shoulder of the first embodiment of the present invention, the friction stir welding tool of the second embodiment of the present invention has basically the same technical effect as the friction stir stationary shoulder of the first embodiment of the present invention.

[0014] The third aspect of the present invention provides a method for using a friction stir stationary shoulder.

[0015] The method for using the friction stir stationary shoulder according to the third aspect of the present invention comprises the following steps: S1: Mounting the stirring head and the friction stirring stationary shoulder of the first embodiment of the present invention on the welding equipment; S2: making the cutting edge face the welding direction, and making the stirring head and the stirring friction static shoulder maintain a predetermined inclination angle in the opposite direction of the welding direction; S3: Start friction stir welding, rotate the stirring needle of the stirring head and penetrate into the product to be welded, and at the same time press the shoulder end face into the product to be welded to a predetermined depth, so that there is a gap between the rear pressure surface and the original surface of the product to be welded. During the welding process, the cutting edge surface is always facing the welding direction, the material guide groove captures the warped burrs overflowing from the outer peripheral edge of the shoulder end face, the cutting edge cuts off the overflowing burrs located radially outside the front end notch of the material guide groove, and the rear pressure surface flattens the burrs captured by the material guide groove and the part after the burrs are cut off by the cutting edge.

[0016] The method for using the stirring friction stationary shoulder of the third aspect of the embodiment of the present invention has the following advantages: the material guide groove and the rear pressure surface can limit the warped burrs overflowing from the peripheral edge of the shoulder end face, the material guide groove can effectively capture the warped burrs at the peripheral edge immediately behind the shoulder end face, the cutting edge can synchronously and effectively cut off the overflowing burrs located radially outside the front end groove of the material guide groove online in real time, the rear pressure surface can effectively flatten the warped burrs captured by the material guide groove and the area after the burrs are cut off by the cutting edge, thereby, the obtained weld is completely burr-free and the weld surface is smooth, so that the post-weld product eliminates the burr removal grinding process.

[0017] In some embodiments, the distance between the cutting edge and the original surface of the product to be welded is 0.1-0.2 mm.

[0018] In some embodiments, the stationary shoulder rotates under the control of the tangential following functional module of the welding equipment so that the cutting edge surface always faces the welding direction.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 A three-dimensional schematic diagram of one orientation of the friction stir stationary shoulder of the present invention; Figure 2a for Figure 1 The enlarged schematic diagram at A in the middle; Figure 2b It is a partial effect diagram of the friction stir stationary shoulder of the present invention; Figure 3A three-dimensional schematic diagram of another orientation of the friction stir stationary shoulder of the present invention; Figure 4 This is a schematic diagram of an application scenario of the friction stir stationary shoulder of the present invention; Figure 5 Schematic diagram of the application scenario of conventional friction stir stationary shoulder.

[0021] Reference numerals: Stirring friction stationary shaft shoulder 1000; shaft shoulder end face 1; material guide groove 2; rear pressure surface 3; cutting edge surface 4; cutting edge 401; stirring head 2000. DETAILED DESCRIPTION

[0022] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0023] Combine the following Figures 1 to 4 The friction stir stationary shoulder 1000 , the friction stir welding tool and the method for using the friction stir stationary shoulder 1000 according to the embodiments of the present invention are described.

[0024] like Figures 1 to 4 As shown, the first aspect of the present invention proposes a friction stirring stationary shoulder 1000 .

[0025] According to the first embodiment of the present invention, the friction stirring stationary shoulder 1000 (reference Figures 1 to 4 ), at the conventional stationary shoulder (reference Figure 5 ), including a shaft shoulder end face 1, a material guide groove 2, a rear pressure surface 3 and a cutting edge surface 4.

[0026] The shaft shoulder end face 1 is as complete as the conventional static shaft shoulder end face and is in a complete ring shape. The shaft shoulder end face 1 is slightly pressed into the product to be welded during welding, that is, the shaft shoulder end face 1 presses the surface position of the product to be welded opposite to the shaft shoulder end face 1 downward by a small amount of displacement, and then the product to be welded will overflow with a raised flash at the peripheral edge of the shaft shoulder end face 1.

[0027] The guide groove 2 is semi-circular on the radial projection surface and is arranged adjacent to the outer rear of the shaft shoulder end face 1. In this way, during welding, the guide groove 2 is located behind the welding and can capture or limit the flash that rises behind the outer rear of the shaft shoulder end face 1.

[0028] The rear pressure surface 3 is semi-circular on the radial projection surface and is closely arranged on the outer periphery of the slot of the guide groove 2, so that the rear pressure surface 3 is separated from the shaft shoulder end face 1 by the guide groove 2 in the radial direction, and the distance between the rear pressure surface 3 and the shaft shoulder end face 1 in the radial direction is the slot width of the guide groove 2; the shaft shoulder end face 1 protrudes from the rear pressure surface 3 in the axial direction, that is, the rear pressure surface 3 is higher than the shaft shoulder end face 1 in the vertical direction, and forms a step difference with the shaft shoulder end face 1, and the step difference is determined by the welding thinning amount of the product to be welded (that is, the position of the weld after welding of the product to be welded becomes thinner than before welding). During welding, the rear pressure surface 3 is at the rear of the welding, and the rear pressure surface 3 does not press into the original surface of the product to be welded, and maintains a suitable gap with the original surface of the product to be welded. The rear pressure surface 3 can limit the flash at the surface position opposite to the rear pressure surface 3 and flatten the warped flash captured by the guide groove 2. It should be noted that if the rear pressure surface 3 is pressed into the original surface of the product to be welded, although it has little effect on the function of removing burrs, it will have an adverse effect on the appearance of the product. If the welding equipment uses a constant pressure welding process, it will also cause certain pressure fluctuations, affecting the welding process.

[0029] The cutting edge surface 4 is vertically arranged at the front end of the rear pressure surface 3 and distributed on the opposite sides of the shoulder end surface 1. The lower end of the cutting edge surface 4 is provided with a cutting edge 401 at the outer side of the material guide groove 2. During welding, the cutting edge surface 4 is always facing the welding direction, that is, facing the welding direction. The cutting edge 401 at the lower end of the cutting edge surface 4 can cut off the overflow flash located at the radial outer side of the front end notch of the material guide groove 2 in real time online, and the part after the flash is cut off by the cutting edge 401 is flattened by the subsequent rear pressure surface 3.

[0030] According to the stir friction stationary shoulder 1000 of the first aspect of the present invention, when in use, the stirring head 2000 and the stir friction stationary shoulder 1000 are first installed on the welding equipment; then the cutting edge surface 4 is made to face the welding direction, and the stirring head 2000 and the stir friction stationary shoulder 1000 are kept at a predetermined inclination angle in the opposite direction of the welding direction; then, the stir friction welding is started, the stirring needle of the stirring head 2000 is rotated and inserted into the product to be welded, and at the same time, the shoulder end face 1 is pressed into the product to be welded to a predetermined depth, so that a suitable gap is maintained between the rear pressure surface 3 and the original surface of the product to be welded. During the welding process, the cutting edge surface 4 is always facing the welding direction, the guide groove 2 captures the warped flying edges overflowing from the outer peripheral edge of the shoulder end face 1, and the cutting edge 401 cuts off the overflowing flash located at the radial outer side of the front end notch of the guide groove 2 in real time online, and the rear pressure surface 3 flattens the flash captured by the guide groove 2 and the part after the flash is cut off by the cutting edge 401, thereby obtaining a weld with no flash after the stir friction welding, and the weld surface is smooth.

[0031] The stirring friction static shoulder 1000 of the first aspect of the embodiment of the present invention has the following advantages: on the one hand, the material guide groove 2 and the rear pressure surface 3 can limit the warped burrs overflowing from the peripheral edge of the shoulder end face 1, the material guide groove 2 can effectively capture the warped burrs at the peripheral edge immediately behind the shoulder end face 1, the cutting edge 401 can synchronously and effectively cut off the overflowing burrs located radially outside the front end groove of the material guide groove 2 online in real time, the rear pressure surface 3 can effectively flatten the warped burrs captured by the material guide groove 2 and the part after the burrs are cut off by the cutting edge 401, thereby, the obtained weld is completely burr-free and the weld surface is smooth, so that the post-weld product eliminates the burr removal and grinding process; on the other hand, the stirring friction static shoulder 1000 is small in size, will not interfere with other components, has interference avoidance, is easy to process, and is inexpensive.

[0032] In some embodiments, the axial distance between the shoulder end face 1 and the rear pressure surface 3 is 0.25~0.5 mm. Since the thinning amount of the product to be welded during welding is usually required to be 0.2~0.3 mm, and it must be ensured that during welding, the shoulder end face 1 is pressed into the product to be welded by a small amount, for example, a small amount of about 0.1~0.2 mm is pressed into the product to be welded, and the rear pressure surface 3 is not pressed into the original surface of the product to be welded, and a suitable gap such as 0.1~0.2 mm is maintained with the original surface of the product to be welded. If the rear pressure surface 3 is pressed into the original surface of the product to be welded, although the function of removing the flash is less affected, it will have an adverse effect on the appearance of the product, and if the welding equipment uses a constant pressure welding process, it will also cause certain pressure fluctuations, which will affect the welding process. Therefore, it is more reasonable to determine that the axial distance between the shoulder end face 1 and the rear pressure surface 3 is 0.25~0.5 mm.

[0033] In some embodiments, the groove depth of the guide groove 2 is 0.5~1.5mm, and the groove width of the guide groove 2 is 0.6~1.5mm. The groove depth and width of the guide groove 2 can be adjusted to a certain extent according to the welding process and working conditions to avoid interference. If the overflowing flash is large, the larger value of the depth and width can be taken. If the overflowing flash is small, the smaller value of the depth and width can be taken. The flash will be tilted to a certain extent during the welding process. Once the flash is tilted, the guide groove 2 can capture the tilted flash, and the rear pressure surface 3 will flatten the tilted flash captured by the guide groove 2. Since the cutting edge 401 maintains a suitable gap with the original surface of the product to be welded during operation, the gap can be 0.1~0.2mm. If the tilted flash exceeds the radial outer side of the front end notch of the guide groove 2 and cannot be captured by the guide groove 2, it will be cut off by the cutting edge 401, and the rear pressure surface 3 will flatten the cut-off part.

[0034] In some embodiments, the minimum length of the cutting edge 401 is 0.4 mm, which can ensure that the overflow flash located at the radial outer side of the front end notch of the material guide groove 2 can be completely cut off.

[0035] In some embodiments, the cutting edge 401 is directly formed at the lower edge of the cutting edge surface 4, which is convenient to process and has a simple structure. Alternatively, a blade is fixed on the cutting edge surface 4, and the blade edge is the cutting edge 401. For example, a threaded hole is opened on the cutting edge surface 4, and a fixing screw passes through the blade and is connected to the threaded hole to fix the blade on the cutting edge surface 4, which is convenient to process and has a simple structure.

[0036] In some embodiments, Figures 2a to 3 As shown, the front side of the cutting edge surface 4 forms an open space area, which is conducive to the timely discharge of the cut flash and does not affect the normal operation of the stationary shoulder.

[0037] A second aspect of the present invention provides a friction stir welding tool.

[0038] The friction stir welding tool according to the second embodiment of the present invention comprises the friction stir stationary shoulder 1000 according to the first embodiment of the present invention.

[0039] Since the friction stir welding tool of the second embodiment of the present invention adopts the friction stir stationary shoulder 1000 of the first embodiment of the present invention, the friction stir welding tool of the second embodiment of the present invention has basically the same technical effect as the friction stir stationary shoulder 1000 of the first embodiment of the present invention.

[0040] The third aspect of the present invention provides a method for using the friction stir stationary shoulder 1000 .

[0041] The method for using the friction stir stationary shoulder 1000 according to the third aspect of the present invention comprises the following steps: S1: The stirring head 2000 and the stirring friction stationary shoulder 1000 of the first aspect of the embodiment of the present invention are installed on the welding equipment; specifically, the stirring friction stationary shoulder 1000 is coaxially clamped on the outer periphery of the stirring head 2000, and the stirring needle of the stirring head 2000 is extended out of the shoulder end face 1, the stirring head 2000 is clamped on the equipment handle, the handle is connected to the spindle rotor, and a certain speed is maintained during operation. The stirring friction stationary shoulder 1000 is installed on the shaft sleeve, and the shaft sleeve is clamped on the spindle housing.

[0042] S2: Figure 2b and Figure 4As shown, the cutting edge surface 4 is facing the welding direction, and the material guide groove 2 and the rear pressure surface 3 are located behind the welding. This is beneficial in the welding process. The material guide groove 2 and the rear pressure surface 3 can limit the warped flying edges overflowing from the peripheral edge of the shoulder end face 1. The material guide groove 2 can effectively capture the warped flying edges at the peripheral edge adjacent to the rear of the shoulder end face 1. The cutting edge 401 can synchronously and effectively cut off the overflowing flash located at the radial outside of the front end groove of the material guide groove 2 online in real time. The rear pressure surface 3 can effectively flatten the warped flying edges captured by the material guide groove 2 and the area after the flash is cut off by the cutting edge 401; and the stirring head 2000 and the stirring friction stationary shoulder 1000 are kept at a predetermined inclination angle in the opposite direction of the welding direction, which is beneficial to a smooth weld and also meets the requirements of the stir friction welding process.

[0043] S3: Start friction stir welding, rotate the stirring needle of the stirring head 2000 and penetrate into the product to be welded, and at the same time press the shoulder end face 1 into the product to be welded to a predetermined depth, so that there is a gap between the rear pressure surface 3 and the original surface of the product to be welded, so as to ensure that the rear pressure surface 3 does not scratch the product to be welded and the weld that has been welded. During the welding process, the cutting edge surface 4 is always facing the welding direction, the guide groove 2 captures the warped burrs overflowing from the outer peripheral edge of the shoulder end face 1, and the cutting edge 401 cuts off the overflow burrs located at the radial outside of the front end notch of the guide groove 2, and the rear pressure surface 3 flattens the burrs captured by the guide groove 2 and the part after the burrs are cut off by the cutting edge 401.

[0044] The method for using the stirring friction stationary shoulder 1000 of the third aspect of the embodiment of the present invention has the following advantages: the material guide groove 2 and the rear pressure surface 3 can limit the warped burrs overflowing from the peripheral edge of the shoulder end face 1, the material guide groove 2 can effectively capture the warped burrs at the peripheral edge adjacent to the rear of the shoulder end face 1, the cutting edge 401 can synchronously and effectively cut off the overflowing burrs located radially outside the front end groove of the material guide groove 2 online in real time, the rear pressure surface 3 can effectively flatten the warped burrs captured by the material guide groove 2 and the area after the burrs are cut off by the cutting edge 401, thereby, the obtained weld is completely burr-free and the weld surface is smooth, so that the post-weld product eliminates the burr removal grinding process.

[0045] In some embodiments, the predetermined inclination angle is 2° to 3°, which is conducive to a smooth weld and also meets the requirements of the friction stir welding process.

[0046] In some embodiments, the distance between the cutting edge 401 and the original surface of the product to be welded is 0.1~0.2mm, so that the cutting edge 401 will not produce scratches on the original surface of the product to be welded and the weld. At the same time, it can effectively cut off the overflow burr located radially outside the front end groove of the guide groove 2.

[0047] In some embodiments, the stationary shoulder rotates under the control of the tangential following function module of the welding equipment so that the cutting edge surface 4 is always facing the welding direction. During the welding feeding process, the rotation of the stationary shoulder is controlled by the tangential following function module, so that even when the stirring head 2000 and the stirring friction stationary shoulder 1000 are turned and welded on the XY plane, the cutting edge surface 4 of the stirring friction stationary shoulder 1000 is always facing the front of the welding, and the guide groove 2 and the rear pressure surface 3 are always behind the welding. To maintain this positional relationship, the main shaft of the welding equipment rotates and feeds synchronously on the XY plane to complete the stirring friction welding, ensuring that the obtained weld is completely free of flash and the weld surface is smooth.

[0048] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0049] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A friction stir stationary shoulder, characterized in that: include: Shoulder end face; A material guide groove, which is semi-circular in shape on a radial projection surface and is arranged adjacent to the outer rear of the shaft shoulder end surface; A rear pressure surface, which is semi-annular in radial projection and is closely arranged around the outer periphery of the slot of the material guide slot, and the shaft shoulder end surface protrudes from the rear pressure surface in the axial direction; The cutting edge surface is vertically arranged at the front end of the rear pressure surface and distributed outside the opposite sides of the shoulder end surface. The lower end of the cutting edge surface is provided with a cutting edge at the outer side of the material guide groove.

2. The friction stir stationary shoulder according to claim 1, characterized in that: The axial distance between the shaft shoulder end face and the rear pressure surface is 0.25-0.5 mm.

3. The friction stir stationary shoulder according to claim 1, characterized in that: The groove depth of the material guide groove is 0.5-1.5 mm, and the groove width of the material guide groove is 0.6-1.5 mm.

4. The friction stir stationary shoulder according to claim 1, characterized in that: The minimum length of the cutting edge is 0.4 mm.

5. The friction stir stationary shoulder according to claim 1, characterized in that: The cutting edge is directly formed at the lower end edge of the cutting edge surface; or, a blade is fixed on the cutting edge surface, and the blade edge of the blade is the cutting edge.

6. The friction stir stationary shoulder according to claim 1, characterized in that: The front side of the cutting edge surface forms an open space area.

7. A friction stir welding tool, characterized in that: It comprises the friction stirring stationary shoulder as described in any one of claims 1 to 6.

8. A method for using a friction stir stationary shoulder, characterized in that: The steps include: S1: Mounting the stirring head and the friction stirring stationary shoulder according to any one of claims 1 to 6 on the welding equipment; S2: making the cutting edge face the welding direction, and making the stirring head and the friction stirring static shoulder maintain a predetermined inclination angle in the opposite direction of the welding direction; S3: Start friction stir welding, rotate the stirring needle of the stirring head and penetrate into the product to be welded, and at the same time press the shoulder end face into the product to be welded to a predetermined depth, so that there is a gap between the rear pressure surface and the original surface of the product to be welded. During the welding process, the cutting edge surface is always facing the welding direction, the material guide groove captures the warped burrs overflowing from the outer peripheral edge of the shoulder end face, the cutting edge cuts off the overflowing burrs located radially outside the front end notch of the material guide groove, and the rear pressure surface flattens the burrs captured by the material guide groove and the part after the burrs are cut off by the cutting edge.

9. The method for using the friction stir stationary shoulder according to claim 8, characterized in that: The distance between the cutting edge and the original surface of the product to be welded is 0.1-0.2 mm.

10. The method for using the friction stir stationary shoulder according to claim 8, characterized in that: The stationary shaft shoulder rotates under the control of the tangential following functional module of the welding equipment, so that the cutting edge surface always faces the welding direction.

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